Revisiting the role of COX-2 inhibitor for non-small cell lung cancer.

Accumulating preclinical and clinical studies have shown that cyclooxygenase-2 (COX-2) inhibitor has some efficacy for non-small cell lung cancer (NSCLC). However, two phase III clinical trials using COX-2 inhibitor in combination with platinum-based chemotherapy showed no survival benefit for "unselected" patients with advanced NSCLC. Thus, exploratory analyses of the association between biomarker and clinical outcome of NSCLC patients treated with COX-2 inhibitors have been warranted. A report by Edelman recently published in the Journal of Clinical Oncology demonstrated the results of a prospective randomized trial using a combination of chemotherapy (docetaxel or pemetrexed) and either COX-2 inhibitor or a placebo for patients with advanced NSCLC. The remarkable point of this study was that it adopted the eligible criteria requiring decreased urinary levels of prostaglandin E metabolite (PGE-M) after administration of COX-2 inhibitor in a run-in period, as a possible predictive marker for the COX-2 inhibitor. The primary endpoint was progression-free survival (PFS). However, no improvement in PFS was observed between the patients treated with COX-2 inhibitor and those with placebo. A number of efforts from various investigators, including this report, have failed to demonstrate the meaningful clinical effect of COX-2 inhibitor for NSCLC. Is COX-2 inhibitor useless anymore? Here, we address the "difficult" character of this COX-2 inhibitor from various viewpoints and discuss potential future strategy using this drug.